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(No Model.)

P. B. RAE; COMPOUND DYNAMO ELECTRIC MACHINE.

,No. 417,089. Patented Dec. 10', 1889.

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UNITED STATES PATENT OFFICE.

FRANK B. RAE, OF DETROIT, MICHIGAN, ASSIGNOR TO THE DETROIT ELECTRICAL IVORKS, OF SAME PLACE.

COMPOUND DYNAMO-ELECTRIC MACHINE.

SPECIFICATION forming part of Letters Patent No. 417,089, dated December 10, 1889.

Application filed May 10, 1889. Serial No. 310,351- (No model.)

To all whom it may concern:

Be it known that I, FRANK B. RAE, a citizen of the United States, residing at Detroit, in the county of Wayne, State of Michigan, have invented certain new and useful Improvements in Compound Dynamo-Electric Machines; and I do hereby declare that the following is a full, clear, and exact description of the invention, which will enable others skilled in the art to which it appertains to make and use the same.

My invention relates to compound dynamomachines, but more particularly to the position and arrangement of the compound winding with relation to the mass of metal. forming the core and pole-pieces of the field-magnets of a dynamo. It is desirable in prac-' tice to place the series winding in such a position that it is independent of the field-magnet windings proper, and may be readily adjusted or interchanged in accordance with the demands of operation. Furthermore, it is essential that such series winding should be placed directly upon the metal comprising the core and pole-pieces of the dynamoz'. a, without the intervention of any intermediate winding between said series coils and the metalthat the m agnetic intensity or saturation of the core can be increased to the maximum by the influence of such series winding.

Accordingly my invention has for its object to attain by a peculiar arrangement and construction of the series coils and the fieldmagnet core the advantages and results above mentioned, and therefore comprises certain details of construction, arrangement, and combination of parts, all of which will be more fully described hereinafter, and the specific points of novelty in which will be definitely pointed out in the appended claim.

In the accompanying drawings. I have shown certain features and parts adequate for successfully carrying out my invention in practice; but since the scope of the claim defining my invention permits many variations and changes from the features illustrated I may make numerous substitutions and changes without in .the least deviating from the fundamental principle of this invention.

Referring to the drawings, Figure 1 is a top plan view of the pole-piece casting of a dynamo-machine provided with seats or recesses for the reception of the series coils. Fig. 2 is a side elevation of the casting shown in Fig. 1. Fig. 3 is a view, partly inside elevation and partly in diagram, of a dynamoeleetric generator, showing my invention complete.

Like letters of reference mark like or corresponding parts in the several views of the drawings.

Referring to Fig. l, A designates a casting formed in one single piece, and consisting of the pole-piece B, having a concave face conforming to the curved periphery of the armature, the yoke-piece C, terminating at each end in the circular portion D, having a screw-threaded orifice a, and the two bearing-brackets E and E, forming a projection at right angles to the yoke-piece C.

As shown in Fig. 3, the dynamo F comprises the two field-magnets G and G, the armature II, the field-magnet cores I and I, and the two castings A and A, there being a casting A placed in a horizontal plane both at the top and the bottom of the dynamo. Each castingA is joined at each end D to its respective field-magnet core I and I in a suitable manner, so that a complete magnetic system or circuit is established through core I, portion D, yoke-piece C, portion D, corepiece 1, portion D, yoke-piece C, and portion D in the direction of the feathered arrow, Fig. The field-magnet windings J and J are wound, respectively, upon cores I and I, and are connected in series to commutator-brushes K and K, as shown clearly in the drawings, Fig. 3.

L, L, L and L respectively indicate four series windings or coils, each removably secured in an are-shaped groove or recess M, formed on the inner side of the casting A intermediate of the portion D and the yokepiece C, and running parallel with the circular line of the portion D-that is to say, the groove or recess M is coincident with a portion of the periphery of the circular portion D, and the chord of the arc-shaped groove M is a chord of an arc of the circular face of the portion D, as will be readily understood by reference to Fi 1. Each groove or recess M is ILO designed to receive and hold in proper posi tion one of the series coils, which, when properly inserted, is either above or below the series winding of the field and has a direct inductive eifect upon the metal comprising the casting A, since it is placed directly upon the casting in groove M. It will be seen that each groove M does not extend entirely around the portion D, but terminates on each side at the edge of the yoke-piece 0. Thus it will be understood that only a portion of each series coil is buried in and supported by this groove M, which is formed for the purpose only of enabling each series coil to be reinovably, independently, and yet securely placed in the field-magnet circuit directly upon the metal casting A and within convenient reach. In other words, by this arrangement each series coil or winding can be readily removed or interchanged without disturbing the shunt-winding, and at the same time its Whole inductive effect can be utilized directly upon the core of the field-magnet.

As shown in Fig. 3, the several coils L LL, and L are connected in series, and the two remaining. terminals are respectively in circuit with the bindii'lg-post N and the cominutator-brush K, the other COllllllIltEt'tOP- brush K being in electrical communication with the other binding-post N. From this the circuits can be readily traced through the entire machine.

Having thus fully described my invention, what I claim, and desire to secure by Letters Patent, is

In a dynamo-electric generator, the combination, with a series coil and shunt-coil, of vertical cores and two horizontal pole-pieces, each of the latter having a circular groove formed therein, bounding the base and top of the core, and of the desired shape and dimensions to accommodate and hold the said series coil in a position independent of the shunt-winding.

In testimony whereof I hereunto set my hand this 8th day of May, A. D. 1889.

' FRANK B. RAE.

Witnesses:

F. R. HARDING, A. D. AYRES. 

